The present invention relates to a radiographic apparatus and, more particularly, to a radiographic apparatus for generating a scout image of a subject by performing, in a rotation movement position to which an irradiator for applying radiation rays and a detector for detecting the radiation rays which have passed the subject are moved so as to rotate around the subject, a scout scan in which the irradiator irradiates the subject with radiation rays, and the radiation rays passed through the subject are detected by the detector.
A radiographic apparatus such as an X-ray CT (Computed Tomography) apparatus generates a slice image of a section of a subject on the basis of projection data obtained by scanning the subject with radiation rays such as X-rays. Such a radiographic apparatus is used in wide-range applications such as medical and industrial applications.
An X-ray CT apparatus performs a scout scan for generating a scout image in order to set scan parameters prior to execution of a scan for generating a slice image.
In the scout scan, an X-ray tube for emitting an X-ray to a subject and an X-ray detector for detecting the X-ray applied from the X-ray tube and passed through the subject are fixed in positions forming a predetermined view angle around the subject. In the fixed position at the predetermined view angle, an X-ray is applied from the X-ray tube to the subject, and the X-ray passed through the subject is detected by the X-ray detector. On the basis of projection data generated by the X-ray detector which has detected the X-ray, a scout image as a radioscopic image of the subject is generated and displayed.
After that, the operator refers to the scout image generated by the scout scan and enters scan parameters such as a slice position corresponding to a section whose slice image is generated. A scan such as an axial scan or a helical scan is performed to generate a slice image of the section in the slice position entered by the operator (refer to, for example, Japanese Patent Laid-Open No. 2005-58651).
The scout scan is performed by fixing, for example, the X-ray tube in front of a chest region of the subject supported in a face-up position on a table and emitting an X-ray from the position.
Consequently, when the subject is a female and a scout scan is performed so as to include a chest region, in some cases, the dose of radiation on the mammary gland having high radiation sensitivity is large and it is difficult to acquire images by effectively using radiation rays such as X-rays. Also in the case of a region having high radiation sensitivity such as a lens in the head of a subject or thyroid in the neck in/around the body surface of the subject, there is a similar inconvenience.
An object of the present invention is, therefore, to provide a radiographic apparatus capable of easily capturing an image by efficiently utilizing radiation rays.